> -----Original Message----- > From: Dexuan Cui [mailto:decui@xxxxxxxxxxxxx] > Sent: Monday, November 24, 2014 8:33 PM > To: gregkh@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; driverdev- > devel@xxxxxxxxxxxxxxxxxxxxxx; olaf@xxxxxxxxx; apw@xxxxxxxxxxxxx; > jasowang@xxxxxxxxxx; KY Srinivasan > Cc: Haiyang Zhang > Subject: [PATCH v2] hv: hv_balloon: avoid memory leak on alloc_error of > 2MB memory block > > If num_ballooned is not 0, we shouldn't neglect the already-partially- > allocated 2MB memory block(s). > > Cc: Jason Wang <jasowang@xxxxxxxxxx> > Cc: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> > Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx> Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> > --- > > v2: I fixed the logic error in v1, pointed by Jason Wang: > In v1: in the case of partially-allocated 2MB, alloc_error is true, > so we'll run "done = true" and hence we won't proceed with > the next iteration of trying 4K allocation. > > I also changed the WARN_ON to WARN_ON_ONCE in case the host > behavior > changes in the future. > > drivers/hv/hv_balloon.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c index > 5e90c5d..b958ded 100644 > --- a/drivers/hv/hv_balloon.c > +++ b/drivers/hv/hv_balloon.c > @@ -1087,10 +1087,12 @@ static void balloon_up(struct work_struct > *dummy) > struct dm_balloon_response *bl_resp; > int alloc_unit; > int ret; > - bool alloc_error = false; > + bool alloc_error; > bool done = false; > int i; > > + /* The host balloons pages in 2M granularity. */ > + WARN_ON_ONCE(num_pages % PAGES_IN_2M != 0); > > /* > * We will attempt 2M allocations. However, if we fail to @@ -1107,16 > +1109,18 @@ static void balloon_up(struct work_struct *dummy) > > > num_pages -= num_ballooned; > + alloc_error = false; > num_ballooned = alloc_balloon_pages(&dm_device, > num_pages, > bl_resp, alloc_unit, > &alloc_error); > > - if ((alloc_error) && (alloc_unit != 1)) { > + if (alloc_unit != 1 && num_ballooned == 0) { > alloc_unit = 1; > continue; > } > > - if ((alloc_error) || (num_ballooned == num_pages)) { > + if ((alloc_unit == 1 && alloc_error) || > + (num_ballooned == num_pages)) { > bl_resp->more_pages = 0; > done = true; > dm_device.state = DM_INITIALIZED; > -- > 1.9.1 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
